Abstract: 1. 1. Metabolic rate (cm3 O2/hr and log cm3 O2/hr) of Viviparus contectoides is dependent on weight and log weight at levels of minimum and intermediate activity in males and minimum activity in females.2. 2. Weight specific oxygen consumption and log weight specific oxygen consumption of V. contectoides is dependent on weight and log weight at levels of intermediate and maximum activity in males and at all activity levels in females.3. 3. Respiration coefficients are affected by activity level or time of day. They decrease significantly with increasing activity level in males. Respiration coefficients are generally lower than literature values.4. 4. The relationship of oxygen consumption to weight is similar for males and females at each level of activity.5. 5. Mean absolute oxygen consumption (cm3/hr) is greater for females than males at each activity level. Mean weight of females is greater than mean weight of males.